Golcadomide and Nivolumab in Patients With Non-Hodgkin Lymphoma With Refractory Disease After Chimeric Antigen T-cell Therapy

Inclusion Criteria: 1. Provision of signed informed consent and willingness to comply with all study requirements for the duration of the study. 2. Patients 18 years of age or older. 3. Patients must have histologically confirmed high-grade large B-cell lymphoma such as diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL grade 3B), primary mediastinal B-cell lymphoma (PMBCL). Patient with transformation from indolent to large cell lymphoma will be allowed to enroll in the study. 4. Presence of FDG avid, radiographically measurable disease (Deauville 4-5) per Lugano 2014 response criteria which will include patients with metabolic partial response (PR), stable disease (SD), and progressive disease (PD), as assessed by the investigator. 5. Patients who received FDA-approved CD19-directed CAR T-cell product(s) (exclusive of any investigational CAR T-cell products). 6. Evidence of measurable residual disease 30 days and up to 1 year after receiving CAR-T therapy. Screening visit should be performed no later than day 365 after CAR-T infusion. 7. Eastern Cooperative Oncology group ECOG performance status ≤ 2. 8. Patients must have adequate organ and marrow function as defined in the protocol at the time of consent. Abnormalities reasonably attributed to underlying lymphoma will be allowed (e.g. anemia due to marrow involvement or LFT elevation due to metastatic involvement) 9. Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load are eligible. 10. For patients with evidence of chronic hepatitis virus infection (HBV or HCV), the viral load must be undetectable on suppressive therapy, if indicated. 11. Patients with CNS relapse (as an extension of systemic disease) are eligible, as determined by the investigator. 12. Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. The malignancy should not be progressing or requiring active systemic treatment within the past year. 13. Patients with known history or current symptoms of cardiac disease should have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification and may require an echocardiogram at the discretion of the investigator. To be eligible for this trial, patients should be class II, stage B or better. 14. Females of childbearing potential (FCBP) must have a negative pregnancy test during screening. 15. All subjects of childbearing potential must agree to use contraceptive methods (hormonal or barrier method of birth control; abstinence) for the duration of the study and for at least 28 days after the last dose of golcadomide. Should a woman become pregnant while she or her partner is participating in this study, she should inform her treating physician and discontinue therapy immediately. Pregnancies (both those of female patients and female partners of male patients) are reported in the same manner as SAEs within 24 hours of the Investigator's knowledge. 16. Ability to take oral medication and be willing to adhere to the golcadomide and nivolumab regimen. Exclusion Criteria: 1. Treatment with any intervening anti-cancer therapies (other than palliative radiation) following CAR-T therapy. This study is intended to be the first treatment of residual disease after CAR-T therapy. 2. Patients who have not recovered from AEs (other than hematologic) of prior anti-neoplastic therapy (i.e., have residual toxicities \> Grade 1) for the exception of alopecia, that require active management. 3. Hypersensitivity reaction to any of the study drugs or their derivatives. 4. Medical or psychiatric co-morbidities that in the opinion of the treating physician may compromise either compliance with or tolerance of study drugs. 5. Patients with GI malabsorption that may compromise absorption of oral golcadomide. 6. Presence of active autoimmune disease. 7. Patients requiring strong CYP3A inducers or inhibitors will be excluded. Note: 1. Avoid coadministration of moderate CYP3A inhibitors and 2. Avoid coadministration of moderate CYP3A inducers until more information regarding the potential DDI risk is available. Patients previously taking strong CYP3A inhibitors/inducers will require a washout period of at least 14 days or 5 half-lives, whichever is shorter, prior to the initiation of study treatment. 8. Currently breastfeeding females.